1. Field of the Invention
This invention relates to an artificial heart apparatus, and more particularly, to ventricular assist devices and a method of manufacturing the ventricular assist devices.
2. The Prior Art
Clinical experience has shown that the cardiovascular circulation of patients in severe or even total heart failure can be sustained with proper left ventricular and right ventricular assist devices (hereinafter "LVAD" and "RVAD," respectively). However, when a heart is in severe left ventricular failure and needs support for the left ventricle, there is a good chance that the right ventricle will begin to fail when it has to cope with the increased return from the left ventricle plus the return from the LVAD. A common experience then is that less and less blood returns from the lungs to the left atrium, and the LVAD's and the patient's cardiac output decrease. Only a few people recover after support to the left ventricle. And, when patients are finally weaned off the LVAD, the long term results are still very disappointing. Of the few patients in the world literature who initially survived, most have died after a few weeks or months.
This experience leads to the conclusion that for serious cases of heart failure, one should aim for long term support rather than support limited to hours, days, or weeks. Further, one should be prepared not to just support the left ventricle, but both ventricles. However, presently there are no LVADs and RVADs that fit easily and properly inside the human chest. Typically LVADs have to be used either in the abdominal cavity or outside the chest. Also, as a rule total artificial hearts fit less than ideally inside the chest. Moreover, production methods for artificial hearts or heart assist devices presently in use are time consuming, cumbersome and unduly expensive. Thus, what is needed in the art are ventricular assist devices which overcome the disadvantages that have been experienced with the prior art type devices.